Question

在代码中，我有：

house = ["red","blue","yellow"];
car = ["fast","big","safe"];
sofa = ["cozy","modern","elegant"];

如何计算并列出代码中的所有数组？
喜欢＆＃34;我有多少个阵列？＆＃34;
回答＆＃34; 3阵列 - 房子，汽车，沙发＆＃34;。

Answer 1

根据您的代码和较少的代码行回答：

var house = ["red","blue","yellow"];
var car = ["fast","big","safe"];
var sofa = ["cozy","modern","elegant"];
var arrayCount = 0;
var arrayString = "";
for (var property in window) {
    if (Array.isArray(window[property])){
        arrayCount++;
        arrayString += arrayCount > 1 ? ", " + property : property;
    }
}
console.log(arrayCount + " arrays - " + arrayString);

检查它是否在https://jsbin.com/mumoxiyire/edit?js,console

上运行

Answer 2

最简单的方法是将所有数组放在一个对象中

var items = require('../app/controllers/itemBackend');
app.get('/api/items/:itemId', items.getItem);

在此示例中，

Arrays = { house: ["red","blue","yellow"], cars: ["fast","big","safe"], sofa: ["cozy","modern","elegant"] } numberOfArrays = Object.keys(Arrays).length; sentence = numberOfArrays + ' Arrays - ' + Object.keys(Arrays).join(', ');将为sentence

Answer 3

var arrayCount = 0;
for (var property in window) {
    var obj = window[property];
    if (Object.prototype.toString.call( obj ) === '[object Array]')
        arrayCount++;
}

console.log(arrayCount);

编辑：最好不要在窗口对象上执行此操作，我在jsfiddle和jsbin上得到不同的结果。产品：＆gt;

Answer 4

那很奇怪。您正在声明所有阵列。所以你总能知道答案。

但你可以在另一个数组包装器中声明它，如下所示：

var items = [["red","blue","yellow"],
             ["fast","big","safe"],
             ["cozy","modern","elegant"]];

然后，您可以通过访问此包装器items.length来获取数组的数量。

Answer 5

如果您有一组相关的数组，则应将它们放在对象中而不是全局命名空间中。然后，您可以调用该对象上的方法来获取有关数组的信息。

var MyArrays = {
  house: ["red", "blue", "yellow"],
  car: ["fast", "big", "safe"],
  sofa: ["cozy", "modern", "elegant"]
};

function countArrays(obj){
  var counter = 0;
  for(var key in obj)
    if(obj[key] instanceof Array)
      counter++;
  return counter;
}
function getArrayNames(obj){
  var names = [];
  for(var key in obj)
    if(obj[key] instanceof Array)
      names.push(key)
  return names;
}

var info = "There are " + countArrays(MyArrays) + " arrays: " + getArrayNames(MyArrays).join(", ");

如何在JavaScript中列出所有数组？

5 个答案: